This invention relates generally to braking systems for bicycles and motorcycles and, more particularly, to braking systems utilizing disc brakes.
The use of disc brakes in motorized vehicles such as automobiles is well known in today's society. However, the extension of this technology to bicycles and other human-powered vehicles is a relatively recent development which has its own special considerations.
The first of these considerations is that of weight. One of the primary goals of bicyclists is to keep the weight of their bicycle to a minimum. Therefore, any braking system used for this purpose must be effective, yet light.
Second, heat dissipation is critical. As a bicycle, or any vehicle for that matter, stops, friction caused by the braking system changes kinetic energy into heat. In traditional bicycle braking systems which use the rim to brake, heat is dissipated freely along the entire circumference of the rim. This occurs because the rims and tires have a large area to absorb and radiate heat away from the rim surface. Further, the tire is in direct contact with the earth. These factors combine to facilitate and promote heat dissipation.
Conversely, the rotors used with disc brakes have a much smaller area than the tires and rims of bicycles. This results in heat being built up quickly and dissipated less effectively. It is common for a bicycle disc brake to reach temperatures in excess of 500 degrees. The heat generated in such a system is transferred to the hub shell where the bearings are located. Heating of the bearings and seals can cause damage.
Third, disc brake systems add to the complexity of the bicycle. Some systems make it difficult to change a tire which is a necessary task to all who ride. If the caliper must be "broken down" for the tire to be removed, the time required for repair and the chance of damage occuring to the caliper system increase significantly. Further, re-alignment of the rotor with the caliper is difficult in many systems.
Finally, existing disc braking systems are generally prone to damage. Unlike the components of a traditional bicycle braking system, a disc braking system utilizes a rotor. The rotor is generally placed on the outside of the wheel and, therefore, not protected. This could put a rider at an extreme disadvantage when riding in rough areas as rocks, branches, and other obstacles can easily damage the rotor.
It is clear that a light-weight and efficient disc braking system is needed that will provide the increased stopping power available from a disc brake while still providing all of the advantages available from a traditional bicycle braking system. The following invention accomplishes these goals.